Present disclosure requires the rights and interests of following U.S. Provisional Patent Application：
No. 61/379,322 of entitled " the Link Adaptation in 802.1lac " of the submission on the 1st of September in 2010U.S. Provisional Patent Application；
No. 61/411,857 U.S. of entitled " VHT Fast Link Adaptation " that on November 9th, 2010 submits toState's temporary patent application；
No. 61/416,154 of entitled " the VHT Fast Link Adaptation " that on November 22nd, 2010 submits toU.S. Provisional Patent Application；
No. 61/430,379 U.S. of entitled " VHT Fast Link Adaptation " that on January 6th, 2011 submits toState's temporary patent application；And
No. 61/451,431 U.S. of entitled " VHT Fast Link Adaptation " that on March 10th, 2011 submits toState's temporary patent application.
The disclosure of all above-cited patent applications is by quoting overall being herein incorporated.
Specific embodiment
Client device in the embodiment being described below, in first network equipment, such as WLAN (WLAN)To second network equipment, access point (AP) the link quality information of such as WLAN.In some embodiments and/or scene,First network equipment is in response to the request for link quality information from second network equipment come link quality information.In some embodiments and/or scene, the link quality information by first network device transmission is uncalled, i.e. the first netNetwork equipment carrys out link quality information on one's own initiative rather than in response to the request from second network equipment.In various embodimentsIn, link quality information has instruction, signal to noise ratio (SNR) information, the received signal strength indicator symbol of modulation and code set(RSSI), the form of the one or more in link margin etc..
Fig. 1 is the block diagram of the exemplary wireless local area network (WLAN) 10 according to one embodiment.AP 14 includes being coupled to netThe host-processor 15 of network interface 16.Network interface 16 includes medium access control (MAC) processing unit 18 and physical layer (PHY)Processing unit 20.PHY processing units 20 include multiple transceivers 21, and transceiver 21 is coupled to multiple antennas 24.AlthoughThree transceivers 21 and three antennas 24 are illustrated in Fig. 1, but in other embodiments AP 14 can include different numbersThe transceiver 21 and antenna 24 of (such as 1,2,4,5 etc.).In one embodiment, MAC processing units 18 and PHY processing units 20It is configured to be operated according to the first communication protocol (for example, being now arranged in the IEEE 802.11ac standards in standardisation process).In another embodiment, MAC processing units 18 and PHY processing units 20 are also arranged to according to the second communication protocol (for example, IEEE802.11n standard) operation.
WLAN 10 includes multiple client station 25.Although four client stations 25 are illustrated in FIG, variousWLAN 10 can include the client station 25 of different numbers (such as 1,2,3,5,6 etc.) in scene and embodiment.Client station 25At least one of client station (for example, client station 25-1) be configured to according at least to the first communication protocol operations.OneIn a little embodiments, at least one of client station 25 client station is not adapted to according to the first communication protocol operations, butIt is configured to according to the second communication protocol operations (referred to herein as " traditional client end station ").
Client station 25-1 includes being coupled to the host-processor 26 of network interface 27.Network interface 27 includes MAC processUnit 28 and PHY processing units 29.PHY processing units 29 include multiple transceivers 30, and transceiver 30 is coupled to multiple daysLine 34.Although illustrating three transceivers 30 and three antennas 34 in FIG, in other embodiments client station 25-1The transceiver 30 and antenna 34 of different numbers (such as 1,2,4,5 etc.) can be included.
In one embodiment, one or two client stations in client station 25-2 and 25-3 have and clientThe 25-1 that stands same or like structure.In one embodiment, client station 25-4 has similar to client station 25-1Structure, but it is not configured as according to the first communication protocol operations.More precisely, in one embodiment, client station25-4 is configured to according to the second communication protocol operations.In various embodiments, be configured to it is identical with client station 25-1 orThe similar client station 25 of person has identical or different number of transceiver and antenna.For example, according to one embodiment, clientEnd station 25-2 only has two transceivers and two antennas.
According to one embodiment, client station 25-4 is traditional client end station, i.e., client station 25-4 is receivedThe communication frame transmitted according to the first communication protocol by AP 14 or another client station 25 is decoded completely.Similarly, according to oneIndividual embodiment, does not enable traditional client end station 25-4 transmit communication frame according to the first communication protocol.On the other hand, traditional visitor is madeFamily end station 25-4 can receive and decode completely and transmit communication frame according to the second communication protocol.
In various embodiments, the MAC processing units 18 and PHY processing units 20 of AP 14 is arranged to generation and meetsThe communication frame of the first communication protocol.Transceiver 21 is configured to transmit generated communication frame via antenna 24.Similarly, receive and dispatchDevice 21 is configured to receive communication frame via antenna 24.According to various embodiments, the MAC processing units 18 of AP 14 and PHY processUnit 20 is configured to process the communication frame for meeting the first communication protocol for being received.
In various embodiments, the MAC processing units 28 and PHY processing units 29 of client device 25-1 is configured to make a livingInto the communication frame for meeting the first communication protocol.Transceiver 30 is configured to transmit generated communication frame via antenna 34.It is similarGround, transceiver 30 is configured to receive communication frame via antenna 34.According to various embodiments, at the MAC of client device 25-1Reason unit 28 and PHY processing units 29 are configured to process the communication frame of the first communication protocol for meeting for being received.
Fig. 2A is the figure of prior art control field 60, and AP 14 and/or client station 25-1,25-2,25-3 are configured toThe control field 60 is transmitted for the purpose of link adaptation to traditional client end station 25-4 and vice versa.In IEEEThe control field 60 defined in 802.11n standards.Include control field 60 in the MAC header of communication frame.Control field 60Including for asking Modulation and Coding Scheme (MCS) and transmit the link adaptation Control Subfield 64 of MCS.Calibrating position son field66 are used to refer to calibrate the position in detection turnaround sequence, and calibrating sequence son field 68 is used to refer to the reality of calibration processExample.Retain son field 70.Channel condition information (CSI)/guiding son field 72 is used to refer to for CSI or beamforming feedbackRequest.Empty packet (NDP) notifies that son field 74 is used for notifying that NDP detection packets will be followed including control field 60Frame.Detection packet is following communication frame, and the communication frame has and permits a determination that multiple-input and multiple-output (MIMO) communication channelThe training field of the estimation of channel, the i.e. communication frame have the training field of the available mimo channel size of detection.
Control frame 60 also includes the son field 76 for retaining.Control frame 60 also includes that access category (AC) constrains the He of son field 78The reverse authorization (RDG) relevant with transmission opportunity (TXOP) holder/more PPDU son fields 80 are allowing another station to existTransmission data during TXOP
Fig. 2 B are the figures of the link adaptation Control Subfield 64 of Fig. 2A.Link adaptation Control Subfield 64 includes the son for retainingField 84 and train request (TRQ) son field 86.TRQ son fields 86 indicate whether to ask the respondent to control field 60 to be transmittedDetection frame.MCS is asked or day line options (ASEL) indicate that (MAI) son field 88 indicates whether to solve Control Subfield 64It is translated into relevant with MCS feedback or relevant with ASEL.When it is value 14 to arrange MAI son fields 88, this is indicated Control Subfield64 be interpreted as it is relevant with ASEL.When it is the value in addition to 14 to arrange MAI son fields 88, this instruction will be solved as shown in FIG. 2 CTranslate Control Subfield 64.Reference picture 2C, when it is the value in addition to 14 to arrange MAI son fields 88, MAI son fields 88 is interpretedIt is to include MCS request (MRQ) son fields 90 and MRQ sequence identifiers (MSI) son field 92.By MRQ son fields 90 be set to 1 withRequest respondent transmits MCS feedback (MFB) in response to receiving control field 60.When it is zero to arrange MRQ son fields 90, noRequest MFB.When it is 1 to arrange MRQ son fields 90, MSI son fields 92 are set for the concrete MRQ of mark, in scope 0 to 6Serial number.When it is zero to arrange MRQ son fields 90, retain MSI son fields 92.
Referring again to Fig. 2 B, link adaptation Control Subfield 64 includes MCS feedback sequence identifier (MFSI) son field 94,The corresponding MSI of MFB in for indicating link adaptation son field 64.For example, requestor can be using (the figure of control frame 602A-2C) and arrange the MSI values in MSI son fields 92 come to respondent send for MCS request.For the response askedThe MSI values that person is sent MCS feedback (MFB) using control frame 60 and is set to MFSI son fields 94 set by requestor.
Link adaptation Control Subfield 64 also includes MCS feedback and antenna select command/data (MFB/ASELC) son field96.When it is value 14 to arrange MAI son fields 88, MFB/ASELC son fields 96 are interpreted as to include ASEL data.On the other hand,When it is the value in addition to 14 to arrange MAI son fields 88, MFB/ASELC son fields 96 are interpreted as to indicate the MCS of suggestion.Value127 indicate not providing MCS feedback (MFB).
According to IEEE 802.11n standards, the network equipment is transmitted with the MRQ son fields for being set to 1 only in situations below90 frame, that is, it is to detect PHY protocol Data Units (PPDU) or ii) notifying NDP to follow (that is, setting NDP to work as the i) frameNotify that 1) son field 74 is and is then followed by the frame of NDP detection packets.
In one embodiment, AP 14 and/or client station 25-1,25-2,25-3 are holding with traditional client end station 25-4Line link be adapted to when utilize control field 60, and traditional client end station 25-4 with AP 14 and/or client station 25-1,25-2nd, control field 60 is utilized when one of 25-3 performs link adaptation.
Fig. 3 A are the figures of the exemplary control word section 120 according to one embodiment, and AP 14 is configured to for link adaptationPurpose and transmit the control field 120 in client station 25-1,25-2,25-3 and vice versa.Control field120 are included for indicating it is should to interpret control word according further to the form illustrated in Fig. 2A according to the form illustrated in Fig. 3 AThe son field 150 of section 120.For example, it is worth (for example, zero), then according to the lattice illustrated in Fig. 2A for first if arranging son field 150Formula interprets control field.On the other hand, if setting son field 150 be second value (for example, one), then according in Fig. 3 A illustrateForm interprets control field.
Indicate that control field 120 whether including uncalled link adaptation feedback, i.e., is not loud using son field 122The link adaptation that should be sent in MRQ is fed back.MRQ son fields 124 are set for one to ask respondent in response to receiving controlField 120 is transmitting MCS feedback (MFB).When it is zero to arrange MRQ son fields 120, MFB is not asked.When setting MRQ son fields124 is the serial number from scope 0-6 for identifying concrete MRQ for the moment, to arrange MSI son fields 126.When setting MRQ son fields124 when being zero, retains MSI son fields 126.
MCS feedback sequence identifier (MFSI)/GID-L son fields 128 are indicated corresponding to the MFB in control field 120MSI.For example, requestor can using control frame 120 and arrange the MSI values in MSI son fields 126 come to respondent send pinRequest to MCS.Respondent to asking sends MCS feedback (MFB) using control frame 120 and by MFSI/GID-L fields128 are set to the MSI values set by requestor.In one embodiment, when arranging son field 122 indicating control field 120When feeding back including uncalled link adaptation, field MFSI/GID-L represents 3 lowest bits of the group ID in reference frame, baseUncalled MFB is calculated in these three lowest bits.
It is used to transmit MFB information and/or the other information relevant with link-quality using MFB son fields 130.Fig. 3 B are rootsAccording to the figure of the MFB son fields 130 of one embodiment.MFB son fields 130 include son field 132, for indicate MFB information and/Or the number of the space-time stream corresponding to the other information relevant with link-quality.Use is provided using MCS son fields 134In the modulation and the instruction of encoding scheme (MCS) of the suggestion used when being transmitted via link.In one embodiment, in advanceDefinition value (such as 15 or another appropriate value) indicates that MCS feedback is unavailable.There is provided using son field 136 except suggestionThe information relevant with link-quality outside MCS and the space-time flow amount of suggestion.In one embodiment, using sub- wordSection 136 is providing signal to noise ratio (SNR) information relevant with link.In one embodiment, SNR information includes following value, the valueIndicate in multiple OFDMs (OFDM) tone or subchannel (for example, all tones, all data tones etc.) withAnd across the flat mean of mean SNR (for example, in units of decibel) of all spatial flows, as measured by respondent.At oneIn embodiment, SNR information is determined according to following formula：And (equation 1)
SNR_FB=Quantized [4 (SNR_avg-22)] (equation 2)
Wherein NSTSIt is spatial flow number,It is data tones number, k is tone index, and NSR is maximum tone ropeDraw value, NSR is minimum tone index value, iSTSIt is spatial stream index, andIt is for i-thSTSIndividual spatial flowThe SNR value of k-th tone.In equation 2, the value in bracket is quantified as into the benefit of 8 bits (or another appropriate bit number) twoYardage (or another appropriate format).
In another embodiment, SNR information includes single SNR value, and the SNR value is the minimum sound among all spatial flowsAdjust average snr value.In another embodiment, SNR information includes：I) indicate in multiple OFDM tones (for example, all tones, instituteHave data tones etc.) in and across the value of the flat mean of mean SNR of all spatial flows, as by measured by respondent；WithAnd ii) single SNR value, the SNR value is the minimum tone average snr value among all spatial flows.In another embodiment,SNR information includes Link Margin value, i.e., between measured SNR and the sensitive point of the MCS indicated by MCS son fields 134Difference.
In another embodiment, son field 136 includes received signal strength indicator symbol (RSSI).
In one embodiment, when setting son field 122 includes uncalled link adaptation to indicate control field 120During feedback, GID-H son fields 138 are effective, and field 138 represents 3 highest bits of the group ID in the frame of reference, based on this3 highest bits calculate uncalled MFB.Include uncalled chain to indicate control field 120 when son field 122 is arrangedDuring the adaptation feedback of road, type of coding son field 140 is effective, and it represents the error control type of coding (BCC in the frame for referring toOr LDPC), uncalled MFB is calculated based on the error control type of coding.When arranging son field 122 indicating control wordWhen section 120 includes that uncalled link adaptation is fed back, feedback Tx Type subfields 142 are effective, and whether it is represented in ginsengShape using following transmission beam in the frame examined, uncalled MFB is calculated based on the transmission beam shaping.
Control field 120 includes the son field 144 for retaining.Control frame 120 also includes that access category (AC) constrains son field146 and the reverse authorization (RDG) relevant with transmission opportunity (TXOP) holder/more PPDU son fields 148, with the TXOP phasesBetween allow another station transmission data.
Use in other embodiments the bit of son field in addition to the example in Fig. 3 A and 3B appropriate sequence andNumber.For example, Fig. 4 A, 4B and Fig. 5 illustrates other examples sequence and the number of bit.
Fig. 4 A are the figures of the another exemplary control field 200 according to one embodiment, and AP14 is configured to for linkAdaptation purpose and transmit the control field 200 in client station 25-1,25-2,25-3 and vice versa.With figureThe exemplary control word section 120 of 3A is similar, control field 200 include for indicate be should according in Fig. 4 A illustrate form alsoIt is interpreting the son field 150 of control field 200 according to form shown in Fig. 2A.For example, if it is first to arrange son field 150Value is (for example, zero), then according to the interpretation control field of form shown in Fig. 2A.On the other hand, if it is second to arrange son field 150Value is (for example, one), then according to the form interpretation control field illustrated in Fig. 4 A.
Control field 200 is similar to the control field 120 of Fig. 3 A, and the element of similar numbering not discussed further.WithThe control field 120 of Fig. 3 A compares, and the son field 204 of reservation and uncalled FB son fields 208 are located in control fieldDiverse location.Additionally, MFB son fields 212 compare with different-format with the MFB son fields 130 of Fig. 3 B.
Son field 216 is similar to the son field 136 of Fig. 3 B, but few two bits of son field 216.Son field 212 is also wrappedInclude bandwidth (BW) son field 220, for indicate for MCS select and/or link-quality determine and with field 134 and/or 216In value it is corresponding receive communication frame bandwidth.When the recipient of control field 200 may not know for MCS select and/orWhen link-quality determination and the bandwidth of communication frame corresponding with the value in field 134 and/or 216, used using BW son fields 220In uncalled feedback (that is, when uncalled feedback son field 208 is arranged to indicate uncalled feedback).OneIn individual embodiment, when uncalled feedback son field 208 is not provided with to indicate uncalled feedback, retain BW son fields220。
Fig. 5 is the figure of the another exemplary control field 250 according to one embodiment, and AP 14 is configured to for linkAdaptation purpose and transmit the control field 250 in client station 25-1,25-2,25-3 and vice versa.With figureThe exemplary control word section 120 of 3A and the exemplary control word section 200 of Fig. 4 A are similar, and control field 200 is included for indicating to beThe son field 150 of control field 200 should be interpreted according further to the form illustrated in Fig. 2A according to the form illustrated in Fig. 5.For example, if son field 150 is set to into the first value (for example, zero), then according to the form interpretation control field illustrated in Fig. 2A.On the other hand, if son field 150 is set to into second value (for example, one), then according to the form interpretation control word illustrated in Fig. 5Section.
Control field 250 and the control field 200 of Fig. 4 A (and with the control field 120 of Fig. 3 A) are similar, and do not enterOne step discusses the element of similar numbering.As in the control field 200 of Fig. 4 A, compare with the control field 120 of Fig. 3 A, protectThe son field 204 stayed and uncalled FB son fields 208 are located at the diverse location in control field.In one embodiment,MFB son fields 130 have the identical form of MFB son fields 130 with Fig. 3 B.
It is when not indicating the value of uncalled feedback and works as MRQ when uncalled FB son fields 208 is arrangedField 124 is set to for the moment, arranges serial number of MSI/ multi-user's (MU) designator son field 254 for the concrete MRQ of mark, asThe example serial number is from scope 0-6.In one embodiment, when uncalled FB son fields 208 are set to indicate that notDuring the value of the feedback of Jing requests, the feedback during the bit of son field 254 is interpreted again to indicate son field 130 whether with single userTransmission or multi-user transmission association.In another embodiment, when by uncalled FB son fields 208 be set to indicate that withoutDuring the value of the feedback of request, MRQ son fields 124 are interpreted again with including be set to indicate that feedback whether with single user transmission orThe bit of multi-user transmission association.
In one embodiment, when the value that uncalled FB son fields 208 are set to indicate that uncalled feedbackAnd when son field 254 indicates that the feedback in son field 130 is associated with single user transmission, two of son field 258 are interpreted againBit with indicate for MCS select and/or link-quality determine and communication frame corresponding with the value in son field 130 bandWidth, and the 3rd bit of son field 258 is interpreted again to be retained.When by uncalled FB son fields 208 be set to refer toShow the value of uncalled feedback, but the feedback that indicates in son field 130 of son field 254 with multi-user transmission when associating, and controlsThe recipient of field processed 250 can based on son field 258 in following group identifier come determine for MCS select and/or linkQuality determination and the bandwidth of communication frame corresponding with the value in son field 130, the group identifier indicates that communication frame is transferred toStation group.In another embodiment, uncalled FB son fields 208 are set to indicate that the value of uncalled feedback, butIt is the feedback that indicates in son field 130 of son field 254 when associate with multi-user transmission, again two of interpretation son field 258 compareThe special bandwidth to indicate for MCS selections and/or link-quality determination and communication frame corresponding with the value in son field 130,And the 3rd bit of son field 258 is interpreted again to be retained.In another embodiment, when by uncalled FB son fields208 are set to indicate that the feedback that the value of uncalled feedback and son field 124 are indicated in son field 130 is transmitted with single userDuring association, again interpret son field 258 two bits with indicate for MCS select and/or link-quality determine and with sonThe bandwidth of the corresponding communication frame of value in field 130.
Fig. 6 is in certain embodiments for transmitting such as above with respect to reference picture 3A-B, Fig. 4 A, Fig. 4 B and Fig. 5 institutesThe figure of the example communication frame 280 of the control frame of discussion.Frame 280 includes Medium Access Control (MAC) Protocol Data Unit (MPDU) 284 and PHY headers286.MPDU284 includes MAC header 288, MAC Service Data Unit (MSDU) 290 and cyclic redundancy check (CRC) (CRC) field 292.Include control field 294 in MAC header 288.In another embodiment, control field 294 is included in PHY headers 286.In one embodiment, control frame 294 has the form as in Fig. 3 A.In another embodiment, control frame 294 has as schemedSuch form in 3B.In another embodiment, control frame has form as in fig. 5.In other embodiments, controlFrame 294 has another appropriate format.Include PHY headers 286 and MAC header 288 in the header portion 296 of communication frame.Therefore,Include control field 294 in header portion 296.
Fig. 7 be in one embodiment for solicited message to perform the flow process of the illustrative methods 300 of link adaptationFigure.In one embodiment, method 300 is by network interface 16 (for example, MAC processing units 18 and/or PHY processing units 20)(Fig. 1) implement.In another embodiment, by network interface 27, (for example, MAC processing units 28 and/or PHY process single to method 30029) (Fig. 1) is implemented for unit.In other embodiments, method 300 is implemented by other appropriate network interfaces.
In block 304, the control field in generating for being included in communication frame.In one embodiment, control field is MACThe field of header and will be included in the MAC headers of communication frame.In one embodiment, control frame has as in Fig. 3 AForm.In another embodiment, control frame has such as the form in Fig. 4 A.In another embodiment, control frame has such as Fig. 5In form.In other embodiments, control frame has another appropriate format.
In one embodiment, block 304 include block 308, block 308 arrange control field son field with indicator to chainThe request of road quality information.In one embodiment, son field indicator is to MCS, SNR information, RSSI, link margin information etc.The request of the one or more of information in.In certain embodiments, block 308 includes arranging MRQ son fields 124 (Fig. 3 A, figure4A or Fig. 5) in value indicating the request.In certain embodiments, block 304 include arranging MSI son fields 126 (Fig. 3 A orPerson Fig. 4 A) or to arrange MSI/MU son fields 254 (Fig. 5) be the concrete request of mark (for example, from scope 0-6 or anotherProper range) serial number.
In one embodiment, block 304 includes block 312, and arranging son field in block 312 will be according to the first communication protocols for instructionView interpretation and not according to the second communication protocol interpreting the value of control field.In certain embodiments, block 312 includes arranging sub- wordSection 150 will not interpret control field according to the interpretation of the first communication protocol with instruction according to the second communication protocol.
In one embodiment, block 304 includes both block 308 and block 312.In one embodiment, block 304 includes block308, but block 304 and method 300 omit block 312.
In block 316, generation is included in the communication frame of the control field of the generation of block 304.In one embodiment, block 316 is wrappedThe MAC header for generating communication frame is included, the MAC header is included in the control field of the generation of block 304.
In block 320, to another device transmission in communication system or cause what is generated in block 316 to another device transmissionCommunication frame.
In one embodiment and in some scenes, the communication frame for generating and transmitting in block 320 in block 316 is notDetection packet and not following communication frame, the communication frame is included in subsequent frame (for example, Empty packet (NDP) notification frame)The instruction of middle transmission Empty packet.In other embodiments and/or scene, generate and in the logical of the transmission of block 320 in block 316Letter frame is detection packet or NDP notification frames.
Fig. 8 is in one embodiment for generating and providing the illustrative methods for performing the information of link adaptation400 flow chart.In one embodiment, method 400 is by network interface 16 (for example, at MAC processing units 18 and/or PHYReason unit 20) (Fig. 1) implement.In another embodiment, method 400 by network interface 27 (for example, MAC processing units 28 and/orPHY processing units 29) (Fig. 1) implement.In other embodiments, method 400 is implemented by other appropriate network interfaces.
In block 404, the first communication frame with the first control field is received.In one embodiment, in the first communication frameThe field of MAC header include the first control field.First control field includes following son fields, and the son field includes being directed toThe instruction of the request of link quality information.In one embodiment, the first control frame has such as the form in Fig. 3 A.In another realityIn applying example, the first control frame has such as the form in Fig. 4 A.In another embodiment, the first control frame has such as the lattice in Fig. 5Formula.In other embodiments, the first control frame has another appropriate format.In certain embodiments, son field is set toMRQ son field 124 (Fig. 3 A, Fig. 4 A or Fig. 5) of the indicator to the request of link quality information.In certain embodiments, willMSI son fields 126 (Fig. 3 A either Fig. 4 A) or MSI/MU son fields 254 (Fig. 5) are set to identify (the example of concrete MRQ requestsSuch as, from scope 0-6 or another proper range) serial number.
In block 408, the MCS of suggestion is determined based on the first communication frame received in block 404.It is all using proper technologyAs known to persons of ordinary skill in the art technology is used to determine the MCS of suggestion.
In block 412, link quality metric is determined based on the first communication frame received in block 404.Using proper technology,All technologies as known to persons of ordinary skill in the art are used to determine link quality metric.In one embodiment, link-qualityTolerance is signal to noise ratio (SNR) tolerance relevant with the first communication frame received in block 404.In one embodiment, SNR toleranceCorresponding to following value, the value indicate with the first communication frame received in block 404 about and the network of such as implementation 400 connectIt is measured by mouthful, in multiple OFDM tones (for example, all tones, all data tones etc.) and average across all spatial flowsAverage SNR (for example, in units of decibel).In one embodiment, SNR tolerance is determined according to equation 1.In another embodimentIn, tolerance is single SNR value, the SNR value be it is relevant with the first communication frame received in block 404, all spatial flows itIn minimum tone average snr value.In another embodiment, SNR tolerance includes：I) indicate and first received in block 404Communication frame is relevant, in multiple OFDM tones (such as all tones, all data tones etc.) and across all space levellingsThe value of mean of mean SNR；And ii) single SNR value, the SNR value be it is relevant with the first communication frame received in block 404,Minimum tone average snr value among all spatial flows.In another embodiment, link quality metric include with block 404The relevant Link Margin value of the first communication frame for being received, that is, the sensitivity of the MCS that the SNR for measuring is indicated with MCS son fields 134Difference between point.In another embodiment, link quality indicator includes relevant with the first communication frame received in block 404Received signal strength indicator symbol (RSSI).
In block 416, the second control field in generating for being included in the second communication frame, to be included in the determination of block 408The instruction of MCS and the instruction of the link quality metric determined in block 412.In one embodiment, the second control field is MAC reportsHead field and will be included in the MAC header of the second communication frame.In one embodiment, the second control frame has as schemedForm in 3A.In another embodiment, the second control frame has such as the form in Fig. 3 B.In another embodiment, the second controlFrame processed has such as the form in Fig. 5.In other embodiments, the second control frame has another appropriate format.In one embodimentIn, include the instruction of MCS in son field 134.In one embodiment, link-quality is included in son field 136 (Fig. 3 A)The instruction of tolerance.In another embodiment, the instruction of link quality metric is included in son field 216 (Fig. 4 A).In a realityIn applying example, the instruction of link quality metric is determined according to equation 2.
In one embodiment, block 416 includes that it is in the first control to arrange MFSI son fields 128 (Fig. 3 A, Fig. 4 A or Fig. 5)The serial number that the MSI or MSI/MU son fields of field (block 404) processed include.In one embodiment, block 416 includes arrangingEither son field 208 (Fig. 4 A or Fig. 5) is following value to son field 122 (Fig. 3 A), and the value indicates to be wrapped in the second control fieldThe link quality information for including is in response to the request for link quality information (for example, in response in the first communication frame (block 404)The first control field).
In one embodiment, block 416 includes block 420, and the son field for arranging the second control field in block 420 will for instructionThe value of the second control field is not interpreted according to the second communication protocol according to the interpretation of the first communication protocol.In certain embodiments,Block 420 includes arranging son field 150 so that indicate will be according to the interpretation of the first communication protocol not according to the second communication protocol interpretation theTwo control fields.In one embodiment, block 416 and method 400 omit block 420.
In block 424, generate the second communication frame to be included in the second control field that block 416 is generated.In one embodimentIn, block 424 includes generating the MAC header of the second communication frame, and the MAC header is included in the second control field that block 416 is generated.
In block 428, to the device transmission for generating the first communication frame (block 404) or so as to the device transmission in block 424The second communication frame for generating.
In one embodiment and in some scenes, block 404 receive communication frame be not detection packet and notIt is following communication frames, the communication frame includes the instruction by Empty packet is transmitted in subsequent frames.In other embodiments and/or fieldJing Zhong, the communication frame received in block 404 is detection packet.
In certain embodiments, block 408 is omitted.In certain embodiments, when block 408 is omitted, block 416 is included theSon field in two control fields is set to indicate that the disabled value of MCS feedback.In one embodiment, son field 134 is setIt is set to the disabled value of instruction MCS feedback.In certain embodiments, when block 408 is omitted, block 416 is omitted and arranges the second controlSon field in field is indicating the MCS of suggestion.
Fig. 9 is in one embodiment for generating and providing the uncalled information for performing link adaptationThe flow chart of illustrative methods 450.In one embodiment, method 450 is by (for example, the MAC processing units 18 of network interface 16And/or PHY processing units 20) (Fig. 1) implement.In another embodiment, method 450 is by (for example, the MAC process of network interface 27Unit 28 and/or PHY processing units 29) (Fig. 1) implement.In other embodiments, method 450 is by other appropriate network interface realitiesApply.
In block 454, it is determined that sending uncalled link quality information to another communication equipment.In a suitable manner, includingDetermine whether that another communication equipment sends uncalled link matter using technology known to persons of ordinary skill in the artAmount information.For example, in one embodiment, it is determined that sending uncalled link quality information based on inspection to another communication equipmentMeasure link-quality to change (SNR, RSSI, PER for for example, increasing or reducing etc.).
In block 458, based on from the communication frame for receiving recently of another communication equipment determining the MCS of suggestion.For trueThe proper technology of the MCS of fixed suggestion, all technologies as known to persons of ordinary skill in the art are utilized.
In block 462, based on from the communication frame for receiving recently of another communication equipment determining link quality metric.OneIn individual embodiment, the communication frame for receiving recently utilized in block 462 is identical with the communication frame utilized in block 458.In another enforcementIn example, the communication frame for receiving recently utilized in block 462 is different from the communication frame utilized in block 458.
For determining the proper technology of link quality metric, all technologies as known to persons of ordinary skill in the art are sharpWith.In one embodiment, link quality metric is signal to noise ratio (SNR) tolerance relevant with the communication frame for receiving recently.OneIn individual embodiment, corresponding to following value, the value indicates and such as implementation relevant with the communication frame for receiving recently to SNR tolerance450 it is network interface measurement, in multiple OFDM tones (for example, all tones, all data tones etc.) with across allThe flat mean of mean SNR (for example, in units of decibel) of spatial flow.In one embodiment, SNR tolerance is determined according to equation 1.In another embodiment, tolerance is single SNR value, the SNR value be it is relevant with the communication frame for receiving recently, all spatial flows itIn minimum tone average snr value.In another embodiment, SNR tolerance includes：I) indicate relevant with the communication frame for receiving recently, in multiple OFDM tones (for example, all tones, all data tones etc.) and across the flat mean of mean of all spatial flowsThe value of SNR；And ii) single SNR value, the SNR value is relevant with the communication frame for receiving recently, among all spatial flowsMinimum tone average snr value.In another embodiment, link quality metric includes the link relevant with the communication frame for receiving recentlyMargin value, i.e., the difference between the sensitive point of the MCS that measured SNR and MCS son fields 134 are indicated.In another embodiment,Link quality indicator includes the received signal strength indicator symbol (RSSI) relevant with the communication frame for receiving recently.
In block 466, the control field in generating for being included in communication frame is being included in the instruction of the MCS of the determination of block 458With the instruction of the link quality metric determined in block 462.In one embodiment, control field be MAC header field andTo be included in the MAC header of communication frame.In one embodiment, control frame has such as the form in Fig. 3 A.In another realityIn applying example, control frame has such as the form in Fig. 3 B.In another embodiment, control frame has such as the form in Fig. 5.At otherIn embodiment, control frame has another appropriate format.In one embodiment, the instruction of MCS is included in son field 134.In one embodiment, in son field 136 (Fig. 3 A) instruction of link quality metric is included.In another embodiment, in sub- word216 (Fig. 4 A) of section include the instruction of link quality metric.In one embodiment, link quality metric is determined according to equation 2Instruction.
In one embodiment, block 466 includes arranging son field 122 (Fig. 3 A) either son field 208 (Fig. 4 A or Fig. 5)The link quality information included to indicate control field is uncalled value.In one embodiment, when determining in block 458MCS and/or block 462 determine link quality metric be based on received single user frame when, block 466 include arrange controlSon field (for example, the son field 220 or the son field 258 of Fig. 5 of Fig. 4 B) in field is with the received single user frame of instructionBandwidth, wherein the MCS determined in block 458 and/or the link quality metric determined in block 462 are based on received single userThe bandwidth of frame.In one embodiment, the link quality metric for determining as the MCS determined in block 458 and/or in block 462 is baseIn receive multi-user's frame when, block 466 include arrange control field in son field (for example, son field 128,138,258) withGroup ID of received multi-user's frame is indicated, wherein the MCS determined in block 458 and/or the link quality metric determined in block 462Group ID based on the multi-user's frame for being received.
In one embodiment, block 466 includes block 470, and the son field for arranging control field in block 470 is instruction by basisFirst communication protocol interpret and not according to the second communication protocol interpret control field value.In certain embodiments, block 470 includesArrange son field 150 to indicate that control field will not be interpreted according to the second communication protocol according to the interpretation of the first communication protocol.In one embodiment, block 466 and method 450 omit block 470.
In block 474, generate communication frame to be included in the control field of the generation of block 466.In one embodiment, block 474 is wrappedThe MAC header for generating communication frame is included, the MAC header is included in the control field of the generation of block 466.
In block 478, it is used for generating the device transmission of the communication frame of MCS and/or link quality information to generation or causesTo the communication frame that the device transmission is generated in block 474.
In certain embodiments, block 462 is omitted.In certain embodiments, when block 462 is omitted, block 466 is omitted and arranges controlSon field in field processed is indicating link quality metric.
With reference to Fig. 8 and Fig. 9, in some embodiments and/or scene, the communication frame transmitted in block 428 or block 479 is receivedCommunication equipment network interface using the MCS (if being included) indicated in control field.In some embodiments and/or sceneIn, the network interface for receiving the communication equipment of the communication frame in block 428 or the transmission of block 479 utilizes what is indicated in control fieldLink quality metric (if being included) will use when the communication equipment to implementation 400/450 is transmitted with being determinedMCS。
Figure 10 is in one embodiment for determining the exemplary of beam forming vector using link quality informationThe flow chart of method 500.In one embodiment, method 500 is by network interface 16 (for example, MAC processing units 18 and/or PHYProcessing unit 20) (Fig. 1) implement.In another embodiment, method 500 by network interface 27 (for example, MAC processing units 28 and/Or PHY processing units 29) (Fig. 1) implement.In other embodiments, method 500 is implemented by other appropriate network interfaces.
In block 504, generate and transmit multiple communication frames to another communication equipment, each communication frame request link quality letterBreath.In one embodiment, using different beams forming vector to transmit communication frame in each communication frame.In one embodimentIn, using such as with regard to Fig. 7 description method to generate communication frame in each communication frame.In one embodiment, using phaseThe multiple communication frames in the transmission of block 504 are transmitted with MCS.
In block 508, receive from another communication equipment and each include link in response to the multiple communication frames transmitted in block 504Multiple communication frames of quality information.In one embodiment, used by another communication equipment next such as with regard to the method for Fig. 8 descriptionsGenerate each communication frame in other communication frames that block 508 is received.
In block 512, based on determining for resuming after to another communication equipment in the link quality information that block 508 is receivedBeam forming vector used in defeated.For example, in one embodiment, the beam forming vector that highest SNR value is provided is selected.MakeFor another example, in one embodiment, the beam forming vector that highest link margin is provided is selected.As another example,In one embodiment, the beam forming vector that highest RSSI is provided is selected.As another example, in one embodiment, utilizeBeam forming vector is generated with the beam forming vector set of highest SNR value, link margin, RSSI etc..Using in block 512It is determined that beam forming vector come to another communication equipment transmit subsequent communication frames.
Figure 11 is in one embodiment for being determined in implicit beamforming using link quality informationThe flow chart of the illustrative methods 600 of the calibration matrix for using.In one embodiment, method 600 is by (the example of network interface 16Such as, MAC processing units 18 and/or PHY processing units 20) (Fig. 1) implement.In another embodiment, method 600 is connect by network27 (for example, MAC processing units 28 and/or PHY processing units 29) of mouth (Fig. 1) are implemented.In other embodiments, method 600 byOther appropriate network interfaces are implemented.
In block 604, communication frame is received from the second communication equipment at the first communication equipment.In the communication frame that block 604 is receivedIt is that there is the communication frame for detecting the training signal of reverse mimo channel.In block 608, based on the communication frame received in block 604Estimate to determine from the second communication equipment to the estimation of the channel of the first communication equipment, i.e. backward channel.
In block 612, estimate to determine that forward channel is estimated based on the backward channel determined in block 604, i.e., from the first communicationEstimation of the equipment to the channel of the second communication equipment.
In block 616, estimate to determine transmission beam forming vector based on the forward channel determined in block 612, i.e., for JingThe beam forming vector being transmitted by forward channel.
In block 620, generate and transmit multiple communication frames of respective request link quality information to the second communication equipment.In one embodiment, using in the beam forming vector that block 616 determines to transmit communication frame in each communication frame.In a realityIn applying example, using different calibration matrixs (for example, to correct the transmitting chain/reception chain between forward channel and backward channelUnmatched calibration matrix) to transmit communication frame in each communication frame.In one embodiment, using such as retouching with regard to Fig. 7The method stated to generate communication frame in each communication frame.In one embodiment, transmitted using identical MCS and passed in block 620Defeated multiple communication frames.
In block 624, receive from the second communication equipment and each include link in response to the multiple communication frames transmitted in block 620Multiple communication frames of quality information.In one embodiment, the second communication equipment is used such as with regard to the method next life of Fig. 8 descriptionsInto each communication frame in the communication frame that block 620 is received.
In block 628, determined for the follow-up of another communication equipment based on the link quality information received in block 624Calibration matrix used in transmission.For example, in one embodiment, the calibration matrix that highest SNR value is provided is selected.As anotherExample, in one embodiment, selects the calibration matrix for providing highest link margin.As another example, in one embodimentIn, select the calibration matrix that highest RSSI is provided.As another example, in one embodiment, there is provided highest SNR value, linkThe calibration matrix set of surplus, RSSI etc. is used for generating calibration matrix.Using the calibration matrix determined in block 512 come logical to secondLetter device transmission subsequent communication frames.
Referring again to Fig. 7 and Fig. 8, in one embodiment, in multi-user communication frame following communication frame is included, the communicationFrame includes the request for link quality information.For example, multi-user downlink transmission in, with multiple client equipment pairThe each subframe answered includes correspondence control field, and these control fields include the request for link quality information.Each clientEnd equipment is responded in corresponding ul transmissions with link quality information.For example, in one embodiment, correspondingAcknowledgement frame includes the link quality information from multiple client equipment.As another example, pass in multi-user downlinkIn defeated, to the NDP notification frames of multiple client device transmission following control fields are being included, the control field is included for chainThe request of road quality information.Each client device is responded in correspondence ul transmissions with link quality information.ExampleSuch as, in one embodiment, the link quality information from multiple client equipment is included in corresponding acknowledgement frame.
Figure 12 is the sequential chart 700 of the exemplary transmission sequence in downlink multiuser MIMO situation.In multi-userAfter detection/feedback procedure, AP transmission multi-users packet 704, multi-user's packet is included for including at least the first clientThe independent data at the multiple client station of (client 1) and the second client (client 2).In a suitable manner, such as in differenceOn spatial flow, it is medium in the different frequency part of channel, simultaneous transmission be used for multiple client station independent data.In a realityIn applying example, packet 704 includes the instruction of the request fed back for MCS and/or link adaptation.Which client packet 704 also includesEnd station should provide the instruction of feedback.In the diagram embodiment of Figure 12, packet 704 include client 1 should provide MCS with/Or the instruction of link adaptation feedback (for example, SNR).Client 1 is transmitted MFB/ link adaptations in packet 708 and is fed back (for example,SNR).In one embodiment, the control field in packet 708 includes that MFB/ link adaptations feed back (for example, SNR).OneIn individual embodiment, in MAC parts (for example, in high-throughput control (HTC) field) of packet 708 MFB/ link adaptations are includedFeedback (for example, SNR).In another embodiment, the control field in the PHY header portions of packet 708 includes MFB.
In one embodiment, packet 708 is to confirm packet.In other embodiments, packet 708 is for transmitting to APAnother appropriate packet of MFB/ link adaptations feedback (for example, SNR).For example, in one embodiment, packet 708 is control envelopeDress (wrapper) frame.In another embodiment, packet 708 is management frame.
Figure 13 is the sequential chart 750 that the another exemplary in downlink multiuser MIMO situation transmits sequence.ManyDuring user's detection/feedback procedure, AP transmission Empty packets notify (NDPA) packet 754.In one embodiment, NDPA pointGroup 754 includes the instruction of the request for MCS and/or link adaptation feedback (for example, SNR).
In one embodiment, NDPA packets 754 indicate that all stations in Basic Service Set (BSS) should provide feedback.In another embodiment, packet 754 also includes which client station should provide the instruction of feedback.In the enforcement illustrated in Figure 13In example, packet 754 includes that client 1 and client 2 should provide the instruction of MFB.For example, client 1 and client 2 should be carriedInstruction for MFB is corresponding with following groups group of ID, and client 1 and client 2 are the members of the group.
Packet 754 indicates that client station should be in response to the follow-up multiuser downstream of the transmission after detection/feedback procedureLink packet 758 and provide feedback.Packet 758 is included for including at least the first client (client 1) and the second clientThe independent data at the multiple client station of (client 2).With appropriate ways, such as on different spaces stream, in the difference of channelFrequency-portions are medium, and simultaneous transmission is used for the independent data at multiple client station.
Client 1 transmits MFB/ link adaptations feedback (for example, SNR) in packet 762.In one embodiment, dividingThe control field of group 762 includes that MFB/ link adaptations feed back (for example, SNR).In one embodiment, in the MAC of packet 762Include that MFB/ link adaptations feed back (for example, SNR) (for example, in high-throughput control (HTC) field) in part.In another realityIn applying example, the control field in the PHY header portions of packet 762 includes MFB.
Client 2 transmits MFB/ link adaptations feedback (for example, SNR) in packet 766.In one embodiment, dividingThe control field of group 766 includes that MFB/ link adaptations feed back (for example, SNR).In one embodiment, in the MAC of packet 766Include that MFB/ link adaptations feed back (for example, SNR) (for example, in high-throughput control (HTC) field) in part.In another realityIn applying example, the control field in the PHY header portions of packet 766 includes MFB.
In one embodiment, packet 762,766 is to confirm packet.In other embodiments, packet 762,766 is to useIn other appropriate packets that MFB/ link adaptations feedback (for example, SNR) are transmitted to AP.For example, in one embodiment, it is grouped762nd, 766 is control encapsulated frame.In another embodiment, packet 762,766 is management frame.
Hardware can be utilized, the processor of firmware instructions is performed, is performed the processor or its any combinations of software instructionCome implement above-described various pieces, operation and technology at least some block, operation and technology.When using perform software orWhen the processor of firmware instructions is to implement, software or firmware instructions can be stored in any computer-readable memory, be countedEither other storage mediums, RAM either ROM or flash memory, processor, the hard disk drive of calculation machine readable memory such as disk, CDDynamic, disc drives, magnetic tape controller etc..It is likewise possible to via any known either desired transfer approach to user or systemTransmission software or firmware instructions, the transfer approach for example computer readable diskette or other can transport Computer Storage mechanismAbove or via communication media.Communication media body generally in data signal, such as carrier wave or other transport mechanisms of modulationExisting computer-readable instruction, data structure, program module or other data.Term " data signal of modulation " means the letterNumber have in the way of such as being encoded to the information in signal to arrange the characteristic for either changing it in one or it is manyIndividual characteristic.It is unrestricted by way of example, communication media include wire medium, such as cable network or direct wiring connection andWireless medium, such as acoustics, radio frequency, infrared ray and other wireless mediums.Therefore, it can via communication channel, such as telephone wire,Either system transmission software or firmware refer to user for DSL lines, cable television line, optical fiber cable, radio communication channel, the Internet etc.Make (it is considered identical or interchangeable with via transmitting software as storage medium is provided).Software or firmware instructionsCan include causing the machine readable instructions of the various actions of computing device when being executed by a processor.
When implementing within hardware, hardware can include discrete parts, integrated circuit, special IC (ASIC), canOne or more in programmed logic device (PLD).
Although with reference to the specific example description present invention for being intended to only illustrate and do not limit the present invention, canTo be changed to disclosed embodiment, add and/or delete without deviating from the scope of the present invention.